<p>We are playing the Guess Game. The game is as follows:</p> <p>I pick a number from <code>1</code> to <code>n</code>. You have to guess which number I picked.</p> <p>Every time you guess wrong, I will tell you whether the number I picked is higher or lower than your guess.</p> <p>You call a pre-defined API <code>int guess(int num)</code>, which returns three possible results:</p> <ul> <li><code>-1</code>: Your guess is higher than the number I picked (i.e. <code>num > pick</code>).</li> <li><code>1</code>: Your guess is lower than the number I picked (i.e. <code>num < pick</code>).</li> <li><code>0</code>: your guess is equal to the number I picked (i.e. <code>num == pick</code>).</li> </ul> <p>Return <em>the number that I picked</em>.</p> <p> </p> <p><strong>Example 1:</strong></p> <pre> <strong>Input:</strong> n = 10, pick = 6 <strong>Output:</strong> 6 </pre> <p><strong>Example 2:</strong></p> <pre> <strong>Input:</strong> n = 1, pick = 1 <strong>Output:</strong> 1 </pre> <p><strong>Example 3:</strong></p> <pre> <strong>Input:</strong> n = 2, pick = 1 <strong>Output:</strong> 1 </pre> <p> </p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 <= n <= 2<sup>31</sup> - 1</code></li> <li><code>1 <= pick <= n</code></li> </ul>